By: Simon Chater
The Point waterfront canal receives its sea water from uShaka Sea World exhibits’ overflow water. This volume varies between 250 – 350 m3/ hour.
In 2003, soon after the canal was filled, uShaka Sea World was approached by the Point Waterfront canal management team to assist in stocking the canal with suitable fish.
Introducing appropriate fish species would serve two purposes: to keep the canal clear of undesirable marine algae growth and to have aesthetically colorful fish for the benefit of residents and visitors strolling along the walkways of the canal. A number of different groups of fish were identified to fit these requirements.
Mullet and surgeonfish were introduced as herbivorous fish and various species of damselfish, wrasses, parrotfish and butterfly fish added visual color and appeal. The shoals of spotted grunter contribute to `turning over’ the sediment substrate on the floor of the canal as they blow into the substrate in search of small molluscs and crustaceans which thrive in the sediment.
Over time however, uShaka Sea World staff noticed a number of undesirable species of fish appearing in the canal which they had not introduced! These included brown stingrays and predatory species such as kingfish, shad, sea pike, rockcod, river snapper and even a Cape yellowtail. These predators prey on other fish and were having a negative impact on the resident fish. With the waterways being freely accessible to the general public it appeared that fishermen had been `illegally’ stocking the canal.
With the permission of DPWMA, uShaka Sea World have also installed a holding enclosure in the canal for species such as Striped bonito waiting to be introduced into the aquarium.
Over thirty five species of fish have, to date, been recorded.
The canal is also home to sea cucumbers, starfish, shrimps, crabs and even oysters. These animals probably arrived in the canal as larvae when the unfiltered water from the North Pier was being pumped into the canal.
The canal is now nearly 14 years old and its animal population is constantly changing. In consultation with the canal management staff, uShaka Sea World staff monitor fish numbers and species, and undertake netting operations at times to remove fish which have become too numerous or too large for the canal. These fish are also generally tagged and released into the sea.
A walk along the canal on a sunny day when the water is clear is an increasingly popular experience, as visitors can watch multitudes of fish going about their business.